Regardless of your preferred source of evidence on treatment effectiveness, it seems that reporting biases are threatening our understanding of the truth (1). Reporting biases arise when the accessible reporting of research findings is influenced by the nature and direction of results. Although the clinician's primary goal of treating patients appropriately and the methodologist's of assuring the quality of research evidence may be different, both want to know “the truth” and are concerned with reporting biases because they affect the conclusions drawn and patient care.

Many clinicians prefer to focus on results from a single or a few selected trials; indeed, they may see systematic reviews and meta-analyses (hereafter “systematic reviews”) as an approach of secondary importance to primary research. Clinicians may believe a trial to be more important because it addresses the question on their minds, it was done by colleagues, it was conducted in a setting and population applicable to their practice, or its findings were published in a reputable journal. Moreover, some clinicians may want to know whether the test intervention works in a subgroup of patients that does not exist in all trials included in a systematic review. In relying on a single or a few trials, however, the clinicians may be forgetting that unreported findings may differ from reported findings (1).